Home > Publications database > Untersuchung der Kristallgitterdefekte und der Kompensationsmechanismen in hoch siliziumdotiertem GaAs mit Hilfe der Rastertunnelmikroskopie |
Book/Report | FZJ-2019-03791 |
1998
Forschungszentrum Jülich, Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/22481
Report No.: Juel-3566
Abstract: The compensation mechanism of silicon (Si) donors in GaAs are determined by scanning tunneling microscopy. With increasing Si concentration the Si donors are consecutively deactivated by Si acceptors, Si clusters, and Si donor-gallium vacancy complexes . A microscopic model based an the screened Coulomb interaction between charged dopants, the amphoteric nature of Si, and the Fermi-level effect is proposed. It explains the observed defects, the critical Si concentrations of each identified mechanism, and predicts the solubility limit of Si in GaAs. The annealing of highly Si-doped GaAs under As atmosphere reduces the concentration of Si atoms incorporated into Si pairs and clusters by cluster dissolution, while the concentration of Si donorsGa vacancy complexes, and Si donor-As vacancy complexes increase. For the dissolution of the Si clusters during heat treatment, a Ga vacancy-mediated mechanism is found. By combining positron lifetime spectroscopy with scanning tunneling microscopy, we observed with increasing Si-doping concentration an increasing concentration of a deep positron trap identified as Si donorgallium vacancy complex. The concentration of shallow positron traps increased with the Si concentration too. The shallow traps are found to be Si acceptors and Si cluster.
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